Core B is a synthesis, analysis and biochemical core that will provide indispensable services for all three projects. The synthetic component of Core B will carry out scaled-up synthesis, purification and analysis of tool-kit and other nucleotide analogs for use in Projects 1 and 3. The biochemical component of Core B is designed to carry out protein purifications and to synthesize specialized DNA constructs required for Projects 1 and 3. The analysis component will be responsible for acquiring and performing global analysis on kinetic data, including presteady state stopped-flow fluorescence intensity and rotational anisotropy, rapid quench experiments, as well as basic NMR and EPR-ENDOR analysis, to be used in support of Projects 2 and 3. Core B will also serve as a primary vehicle for training graduate and postdoctoral students in chemical synthesis and protein purification techniques, the principles and practice of enzyme kinetic analysis, and techniques in experimental NMR and EPR spectroscopy.